The invention provides a method for forming a self-aligned contact portion. The method comprises the steps of: providing a substrate, wherein a gate stack and side walls arranged on both sides of the gate stack are formed on the substrate, and source/drain regions and metal silicide layers arranged on the source/drain regions are formed on the substrate on two sides of the side walls; forming barrier mask layers and second side walls which are arranged outside the side walls and on the barrier mask layer in sequence; forming an interlayer dielectric layer, and carrying out surface planarization until the gate stack is exposed; removing the second side walls and the barrier mask layers connected with the second side walls, and exposing the metal silicide layers; filling grooves with metal and carrying out planarization until the gate stack is exposed. The method for forming the self-aligned contact portion can effectively solve the problem that the distance between the gate and the contact portion cannot be precisely and easily reduced in the prior art.